Shaun Merrigan
Classic Electronic Restoration, Vacuum Tube Audio, Technical History, Photography
Category: Restoration of Classic Electronic Test Equipment
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In a recent post, I documented the replacement of a difficult to read VFD display with a modern TFT display in my Advantest R6581T. It was unequivocally worthwhile and has been working extremely well. Nowl, I am at it again, but his time the subjects are the HP 3478A 51/2 digits DMM and the HP…
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The Advantest R6581T is an 8.5‑digit, rack‑mount digital voltmeter (DVM) built for high‑precision DC measurements; the T variant is a DC‑only field/rack model (no AC TrueRMS option) and is prized on the used market for lab and calibration work—buyers should expect to source units secondhand and verify display/health before purchase. Overview Notable Features and Design…
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This is a follow-up to my previous post about repairing a Tektronix CG551AP/CG5001 Calibration Generator. The CG551 had been sitting for many months and I thought it was time to give it a quick check. Shortly after turning on the TM5000 mainframe that I had plugged the CG551 into, I was assaulted by the tell-tale…
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I documented the repair of two Tektronix DM 5010 digital voltmeters here. I will not rehash the entire calibration process here. That is easily found in the manual for the DM 5010 which is available on the Tek Wiki. Rather, I will highlight items which may help readers avoid pitfalls and save time. Equipment Needed:…
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The HP 3445A is a compact, rackable plug‑in digital voltmeter from Hewlett‑Packard’s classic 34xx family, offering fast autoranging DC and AC measurements, clear numeric readout, and system‑friendly outputs that made it a staple in production racks and vintage labs. HP 3445A overview The 3445A is a plug‑in digital voltmeter designed for HP’s modular instrument systems,…